Electronic locks provide a very high degree of security. The electronic locks may take any of several forms but particularly electronic combination locks have provided the highest degree of security. Key operated locks which electronically read combinations on keys also may provide a very high degree of security. However, the security of these types of locks is severely comprised in the event an operator is forced to operate or open the safe, vault or other security container while under duress or threat of harm. In the event of an opening by the operator under duress, the lock itself no longer offers a satisfactory degree of security. When a person operating the lock under duress is forced to open the lock or to provide the combination to an unauthorized user, it is known that delayed access to the container for a reasonable period of time is sufficient in many instances to cause the unauthorized user to abandon the attempt to gain access to the contents of the container. Such a delay of access to the container during a robbery may be sufficient to cause abandonment of this effort because of the added apprehension exposure to perpetrators who may not be able to afford the additional time delay inasmuch as it may expose them to the possibility of apprehension by either security or law enforcement personnel.
A lock which thus provides a very high degree of security is the Mas-Hamilton X-07 lock, obtainable from the Mas-Hamilton Group, Lexington, Ky. This lock may be modified and improved to provide a delay function, thereby denying access to any container upon which the lock is mounted, for a predetermined time period once the combination to the lock has been correctly entered. Other electronic locks also may be used for the base of the implementation of the improvement described herein. For example, the time delay may be implemented on an electronic key operated bolt lock of the type described in co-pending patent application Ser. No. 763,119, filed Sep. 20, 1991, for Electronic Bolt Lock With Enhanced Security Features by Gerald L. Dawson, et. al., and commonly assigned herewith.
While the delay factor is probably the most significant to prevent unauthorized access to security containers such as vaults, safes or other cabinets, it is a common procedure to notify security personnel or a security agency whenever a lock or a vault is being attacked. When this notification alarm capability is combined with the timed delay briefly described above, the security of the locked container will be further enhanced.
It is common to provide alarms to locked containers which then signal whenever the lock is being attacked or being tampered with; and, this function typically requires electrical conductors or a cable which connects the lock mechanism or the lock frame with an alarm which is displaced from the lock or security container. This alarm is usually referred to as a silent alarm, inasmuch as the signal activates an alarm device at a remote location and gives no indication at the location of the container, that a remote alarm has been activated. The alarm will notify personnel of either a security center or a law enforcement agency of any attempt to tamper with the lock so alarmed.